A method has been known that predicts failures of an HDD (hard disk drive), and automatically makes a backup or recommends backing up when a failure is predicted. Another method has been known that preferentially backs up files with high priority. Furthermore, a method has been known that backups may be periodically made. Moreover, a method has been known that when files are updated, differences may be automatically backed up. There are commercial backup tools, such as ARCserve, Backup Exec, and NetVault. These tools make backups irrespective of the failure probabilities of HDDs.
As described above, the method that predicts failures and makes a backup has already been known. Furthermore, the method of preferentially backing up files with high degrees of importance has already been known.
However, the effect of the conventional methods is data preservation of a HDD at the time when a failure is predicted. Unfortunately, there is no advantageous effect of achieving continuous data preservation even after failure prediction due to optimization of backup intervals before and after detection of a failure symptom and due to optimization of a replacement reference.
In the present situation, backup is a good faith effort by PC users, but is not managed in most cases. Conventionally, only when a failure is predicted, backup is automatically performed or recommended. However, an appropriate backup interval for continuous backup after detection of a failure symptom has been unknown. Typically, replacement of PCs and HDDs are determined on the basis of an elapsed time after installation. Thus, an optimal replacement reference based on the failure risk of the entire PC/HDD to be managed has not been determined.